Impact of variability of Nakagami-m parameter on the performance of digital communication systems

Arabic Abstract

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English Abstract

The effect of varying distances between the mobile station and base station on the Nakagami-m parameter is studied. For this purpose a path loss model is developed that finds out the received direct and scattered powers at the mobile station. The effect on the Nakagami-m parameter for different distributions of the reflection co-efficient π is presented. It is found that the exponential distribution gives larger values of m as compared to uniform and half Gaussian distribution. Change in the operating frequency also affects the performance of a digital communication link. A new parameter Δm is also introduced in order to study the change in performance behavior of the system with increase in distance. It is, also, observed that the transmitter and receiver antenna heights affect the Nakagami-m parameter and an increase in their effective value enhance the performance of the system. The degraded performance at larger distances for smaller values of Nakagami-m parameter is studied and the error rates are improved by using coherent Equal Gain Combining (EGC) for flat fading and Rake demodulator for frequency selective fading channels. The effect of different parameters such as transmitter and receiver antenna heights, propagation environment, operating frequency, distribution of the reflection coefficient and the distance between the mobile station and the scatterers and studied over the proposed model.